Questions tagged [delay]
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160 questions
2 votes
2 answers
217 views
Why use Sliding DFT over Delay method for re-using old FFT with new samples
The sliding DFT, as shown here, appears with what appears to be the following formulation: $$Y[k] = e^{j2\pi\frac{k}{N}}\left(X[k] + a - x[N-1] \tag{1}\right)$$ The delay formulation https://dsp....
- 133
2 votes
1 answer
128 views
How to perform timing synchronization for a signal with a preamble
Let's say i have a signal with about 300 symbols for initial preamble and 50 symbols for the mini-preamble that comes after every data frame, data frame of 200 symbols per frame. The frame structure ...
- 89
0 votes
0 answers
20 views
Compensating optimal PD gains for a simple two-state linear system with different position/velocity measurement delays
Consider the following approach for de-rating proportional feedback gains to account for a measurement delay by controlling a future-projected response: In practice, I've found this works pretty well ...
- 101
1 vote
1 answer
121 views
Do the delay and differentiation operators always commute?
Let $D_{\tau}$ be the delay operator, $T$ be the differentiation operator, and $x(t): \mathbb{R} \to \mathbb{R}$. Then $D_{\tau} x(t) = x(t-T)$ and $Tx(t) = x'(t)$. To check commutativity, we want to ...
- 13
1 vote
1 answer
58 views
Converging behaviour with upsampling in cross-correlation analysis
I have performed a cross-correlation analysis using scipy.signal.correlate to determine the phaseshift (time delay) between two sine waves that I have recorded with a 180MHz digitizer. To increase the ...
- 11
0 votes
1 answer
63 views
Moving Average Filter. General Form of a Filtered Signal. How to Determine the Phase Shift?
Let's consider the following filter $$y[n]=\frac{1}{3}(u[n-2]+u[n-1]+u[n])$$ and $M=3$, $k=\overline{0,2}$ with $$u[n]=\sin\left(\frac{\pi}{10}n\right)+\sin\left(\frac{\pi}{4}n\right)+\sin\left(\frac{...
- 105
0 votes
0 answers
52 views
Synchronize multiple digital signals sampled at different frequencies
I am recording videos using multiple raspberry pis. Some videos are sampled at 30Hz, others at 90Hz and they start at different times. On each frame I also record digital inputs for offline ...
- 101
2 votes
0 answers
95 views
Delay window function (including fraction delay value)
Introduction - Context I am trying to implement some truncated/windowed $\operatorname{sinc}(\cdot)$ fractional delay. I have managed to get “correct” results (compared to an implementation known to ...
user40198
1 vote
2 answers
79 views
Fourier transform - connection between delaying $k$ steps as $e^{-jkω}$ and magnitude of the frequency $\omega$
Trying to understand what Fourier transform does. In my understanding, if there is a discrete signal $f_k$ where $k$ is an integer sample index ranging from $-\infty < k < \infty$, Fourier ...
- 183
2 votes
0 answers
29 views
Time delay estimation for superimposed random signals sampled from a multivariate Gaussian mixture?
Suppose my signal model is: $$ \mathbf{y} = D(\tau_1) \mathbf{x}_1 + D(\tau_2) \mathbf{x}_2 $$ where $D(\tau)$ is a delay matrix that shifts a signal by $\tau$ samples. $\mathbf{x}_1$ and $\mathbf{x}...
- 45
0 votes
1 answer
82 views
Calculating the signal shift of acoustic emissions between a source and an observer
I am attaching two sensors on a body that I would like to investigate for defects. I am creating an impulse response on the first sensor by hitting the bolt that it is fastened by with a sharp object ...
- 103
2 votes
2 answers
210 views
How do you interpret the sign (positive, negative or zero) of the phase spectrum?
How do you interpret the sign (positive, negative or zero) of the phase spectrum of: 1)a digital filter (the phase spectrum of its frequency response aka phase response of the filter). 2)a signal in ...
0 votes
2 answers
191 views
Audio delay with feedback
I'm writing a simple "audio delay effect", with feedback (the closer FEEDBACK from 1, the more the repetitions ...
- 1
0 votes
1 answer
718 views
Time delay vs phase ramp, group delay and phase delay
I need to apply a phase ramp in the frequency domain to a signal in order to apply a delay to it in the time/digital domain. However, I am confused by the fact that if I convert the phase ramp into ...
- 41
2 votes
3 answers
850 views
Wideband phase vs time delay beamforming correction
I am studying a 1D beamforming for wide-band signals, so that applying only phase weights to each individual antenna would steer the beam for the central frequency. For other frequencies the steering ...
- 41